二维C/C复合材料的断裂韧性研究

The fracture toughness of 2D carbon-carbon composite

进行了炭布增强二维C/C复合材料的平面应变断裂韧性(KⅠc)和层间断裂韧性(GⅡc)研究,它们的测试分别采用了单边缺口梁(SENB)弯曲法及端部切口弯曲法(ENF)。结果表明,2D C/C垂直于炭布铺层方向的断裂韧性KⅠc为5.48MPa·m1/2,是毡基C/C的4倍,但稍低于针刺C/C。2D C/C的层间断裂韧性随测试温度的升高而增加,在2000℃裂纹扩展的临界载荷是室温时的2倍,而层间断裂韧性则提高了4倍。这说明2D C/C在高温下抗层间裂纹的扩展能力增大,这一结果对实际应用带局部小面积缺陷的新型2D C/C部件提供了更大的设计自由度和安全可靠性。

The plane strain fracture toughness (KⅠc) and interlaminar fracture toughness (GⅡc) of carbon cloth reinforced 2D carboncarbon composites are discussed.KⅠc and GⅡc were measured by means of the single edge notched beam (SENB) bending and the edge notched flexure (ENF)respectively.The results show that KⅠc of 2DC/C is 5.48MPa·m1/2,3 times bigger than that of felt based C/C and a little lower than that of needled C/C.GⅡc increases as measuring temperature rises.At 2 000℃ the critical load for crack propagation is 2 times as that at RT,while GⅡc at 2 000℃ 4 times bigger than that at RT.It shows the capacity of anticrack propagation for 2DC/C is improved at elevated temperature.The resulf offers more design freedom and reliability for practical use of the 2DC/C components with small area delamination and defects.